JPS6315639Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a mechanism for preventing loosening of a power transmission rope, and in particular, in a serial printer, etc., the present invention relates to a mechanism for preventing loosening of a rope for transmitting power. The present invention relates to a loosening prevention mechanism that can constantly adjust and control the tension of a power transmission rope connected to the ink ribbon cassette and stretched so as to move an ink ribbon cassette up and down.

(b) Background of the technology In serial printers, etc., one end is fixed to a carriage movable in the print line direction on which a printing mechanism such as a printing head and two-color ink ribbon cassette is mounted, and the other end is fixed to a carriage that is movable in the printing line direction. A power transmission pulley is provided that is connected to the vertical motion biasing section and stretched between two pulleys that are arranged at a predetermined interval in the printing line direction. By pulling one of the unfixed pulleys outward (in the tensioning direction) using a magnetic drive means as necessary, the vertically movable biasing section connected to the other end of the rope is actuated. The printing color of the ink ribbon is switched by pushing up the two color ink ribbon cassettes.

(c) Prior Art and Problems By the way, the power transmission rope, which is stretched between the two pulleys in order to perform the ribbon color switching function stably and reliably at all times, is , in order to widen the distance between the two pulleys, one of the non-fixed pulleys can be adjusted by a fine adjustment mechanism to separate the other semi-fixed pulley, and a constant tension state is maintained. There is. However, in the above-mentioned structure in which the power transmission rope is stretched, if the rope stretches during the operation of the carriage on which the printing mechanism is mounted, the stretch of the rope is automatically absorbed and the rope is stretched. Printing problems occur because there is no mechanism to correct the rope to a predetermined tension state. For this reason, the conventional method has the drawback that every time the rope is stretched, it is necessary to stop the printing operation of the device and slightly adjust the position of the other pulley to readjust the tension state of the rope to the specified value. Ta.

(d) Purpose of the invention In order to eliminate the above-mentioned drawbacks of the conventional technology, the present invention provides a power transmission system that is connected to both ends of a moving body consisting of a carriage, and is suspended between two pulleys arranged at a predetermined distance. It automatically absorbs the elongation (slack) of the rope without the operator having to readjust it.
It is an object of the present invention to provide a mechanism for preventing loosening of a power transmission rope, which can always adjust the rope to a predetermined tension state.

(e) Structure of the invention According to the invention, the above object is to always control the tension of a rope stretched between two pulleys connected to both ends of a moving body and arranged at a predetermined interval. a spiral spring for fixing one end of the rope to a rotating body pivotally supported by the movable body so as to be rotatable in the rope tensioning direction, and for rotating the rotating body in a direction that applies tension to the rope; and a reverse rotation prevention means for preventing the rotating body from rotating in a direction opposite to the direction of rotation by the spiral spring. will be achieved.

(f) Embodiments of the invention Hereinafter, embodiments of the invention will be described in detail using drawings.

FIG. 1 is a front view of essential parts showing an embodiment in which the present invention is applied to an ink ribbon color switching mechanism in a serial printer. 4 is a printing carriage movable in the printing line direction shown by arrow A, one end of which is connected to one end of a lever 51 of a printing color switching function section 5 for the two-color ink ribbon cassette on the printing carriage 1; A first pulley 7 and a second pulley 8 whose ends are connected to the rope loosening prevention mechanism 6 of the present invention attached to the main body of the printing carriage 1, and which are arranged at a predetermined interval in the printing line direction. This is a power transmission rope strung between the two. The tension of the power transmission rope 4 stretched in this way is basically adjusted to a predetermined value by the tension adjustment mechanism 11 attached to the shaft support 10 of the second pulley 8, as before. ing. Further, as before, the first pulley 7 is also supported by the shaft support 9 and is normally positioned by being pressed toward the stopper 12' by the pressing spring 12.
is excited by the ribbon color switching signal to attract the shaft support 9 (armature) toward the electromagnet 13 and pull the rope 4 outward (to the right in the paper), thereby switching the printing color. As a result of rotating the lever 51 in the direction of arrow B about the pivot point 52 and moving the pin 53 upward, the two-color ribbon cassette is pushed up and the color is changed.

On the other hand, as shown in the enlarged partial view of FIG.
a ratchet wheel 23 rotatably disposed on a central support shaft 22 and provided with a rope connection portion 24;
a rotary body, and one end is attached to the central support shaft 22 in the recess 25 of the ratchet wheel 23 so that the ratchet wheel 23 rotates in the direction of applying tension to the connected rope 4, that is, in the direction of arrow C. , a spiral spring 2 whose other end is fixed to a ratchet wheel 23 as shown in the figure.
6, and a reverse rotation stopper 27 for preventing the rotation thereof. Therefore, as shown in FIG.
The power transmission rope 4 is stretched between the pulley 7 and the second pulley 8 and is adjusted to a predetermined tension by the tension adjustment mechanism 11 attached to the shaft support 10 on the second pulley 8 side. , even if the printing carriage 1 stretches during operation, the tension of the spiral spring 26 of the rope loosening prevention mechanism 6 causes the rope 4 to stretch.
The ratchet wheel 23 to which the other end is connected rotates in the direction of arrow C, and the slack in the rope 4 is automatically absorbed and the rope is adjusted to a predetermined tension state, so that the predetermined tension state can be stably maintained at all times. It becomes possible. Note that since the reverse rotation stopper 27 is always engaged with the ratchet wheel 23, when the first pulley 7 is moved outward by the electromagnet 13 and the rope 4 is pulled, the corresponding The ratchet wheel 23 never rotates in the opposite direction.

(g) Effect of the invention As is clear from the above explanation, the power transmission rope loosening prevention mechanism according to the invention is connected to a movable body such as a printing carriage at both ends, and is arranged at a predetermined interval. With a simple configuration, the tension of the power transmission rope stretched between two pulleys is automatically maintained at the specified tension without the operator having to readjust it to the specified tension each time. It is possible to adjust the condition and maintain it stably. Therefore, it is extremely advantageous to apply the present invention to various printers or other devices having a structure similar to the power transmission rope tension structure described in this embodiment.

[Brief explanation of drawings]

Fig. 1 is a front view of main parts showing an embodiment in which the power transmission rope loosening prevention mechanism according to the present invention is applied to an ink ribbon color switching mechanism of a serial printer, and Fig. 2 is a power transmission rope according to the present invention. FIG. 3 is a front view showing an example of the loosening prevention mechanism of FIG. In the drawing, 1 is a printing carriage, 2 is a printing head, 3 is an ink ribbon cassette, 4 is a rope for power transmission, 5 is a printing color switching function section, 6 is a rope loosening prevention mechanism, 7 is a first pulley, and 8 is a first pulley. 2 pulley, 9 and 10 a shaft support, 11 a tension adjustment mechanism,
12 is a pressure spring, 13 is an electromagnet, 21 is a mechanism fixture, 22 is a central support shaft, 23 is a ratchet wheel, 24 is a rope connection part, 25 is a recess in the ratchet wheel 23, 26 is a spiral spring, and 27 is a reverse rotation stopper. Indicate the ingredients.

Claims (1)

[Scope of utility model registration request] In order to constantly control the tension of the rope stretched between two pulleys connected to both ends of the moving body and arranged at a predetermined interval, one end of the rope can be rotated in the rope stretching direction. a spiral spring fixed to a rotating body that is pivotally supported by the moving body and for rotating the rotating body in a direction that applies tension to the rope; and a spiral spring that rotates the rotating body in a direction opposite to the direction of rotation by the spiral spring. A mechanism for preventing loosening of a power transmission rope, characterized in that it is provided with a reverse rotation prevention means for preventing the rotation from occurring.